U.S. patent application number 14/296616 was filed with the patent office on 2015-01-29 for methods for polyolefin polymerization with high activity catalyst systems.
The applicant listed for this patent is ExxonMobil Chemical Patents Inc.. Invention is credited to Todd S. Edwards, Kevin W. Lawson.
Application Number | 20150031842 14/296616 |
Document ID | / |
Family ID | 49223637 |
Filed Date | 2015-01-29 |
United States Patent
Application |
20150031842 |
Kind Code |
A1 |
Edwards; Todd S. ; et
al. |
January 29, 2015 |
Methods for Polyolefin Polymerization with High Activity Catalyst
Systems
Abstract
A method is provided for polymerizing an olefin monomer in a
reactor with a highly active polyolefin polymerization catalyst
system. The method includes introducing a catalyst system
comprising a catalyst and a catalyst activator into the reactor
containing the olefin monomer with less than 10 seconds or no
pre-contacting time of the catalyst and the catalyst activator
prior to introducing the catalyst and the catalyst activator into
the reactor. The catalyst system may have a standard adjusted
catalyst activity of greater than 10 gPgcat.sup.-1hr.sup.-1.
Inventors: |
Edwards; Todd S.; (League
City, TX) ; Lawson; Kevin W.; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Chemical Patents Inc. |
Baytown |
TX |
US |
|
|
Family ID: |
49223637 |
Appl. No.: |
14/296616 |
Filed: |
June 5, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61858457 |
Jul 25, 2013 |
|
|
|
Current U.S.
Class: |
526/64 ; 526/213;
526/226; 526/348; 526/351; 526/90 |
Current CPC
Class: |
C08F 110/06 20130101;
C08F 2/00 20130101; C08F 210/06 20130101; C08F 10/00 20130101; C08F
2500/12 20130101; C08F 2500/04 20130101; C08F 110/06 20130101 |
Class at
Publication: |
526/64 ; 526/351;
526/90; 526/348; 526/226; 526/213 |
International
Class: |
C08F 210/06 20060101
C08F210/06 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 20, 2013 |
EP |
13185277.4 |
Claims
1. A method for polymerizing an olefin monomer in a reactor with a
highly active polyolefin polymerization catalyst system comprising:
introducing a catalyst system comprising a catalyst and a catalyst
activator into the reactor containing the olefin monomer with less
than 10 seconds or no pre-contacting time of the catalyst and the
catalyst activator prior to introducing the catalyst and the
catalyst activator into the reactor; wherein the catalyst system
has a standard adjusted catalyst activity of greater than 10
gPgcat.sup.-1hr.sup.-1.
2. A method for polyolefin polymerization comprising: introducing
(i) a Ziegler-Natta catalyst having a Ti polymerization site and an
internal electron donor and (ii) a catalyst activator into a
reactor containing an olefin monomer with less than 10 seconds or
no pre-contacting time of the catalyst and the catalyst activator
prior to introducing the catalyst and catalyst activator into the
reactor.
3. A method for polyolefin polymerization comprising: introducing a
catalyst system into a reactor containing an olefin monomer;
wherein the catalyst system comprises: a catalyst having a titanium
polymerization site in a Ti(IV) state, an activator suitable for
reducing the titanium polymerization site from the Ti(IV) state to
an activated Ti(III) state; and wherein the catalyst and the
activator are introduced into the reactor with less than 10 seconds
or no pre-contacting time.
4. The method of claim 1, further comprising producing a polyolefin
polymer.
5. The method of claim 1, wherein the reactor is a
pre-polymerization reactor.
6. The method of claim 1, wherein the reactor is a slurry loop
reactor.
7. The method of claim 1, wherein the olefin monomer is
propylene.
8. The method of claim 1, wherein the reactor further comprises a
second monomer.
9. The method of claim 8, wherein the second monomer is ethylene or
a C.sub.4-C.sub.10olefin.
10. The method of claim 1, wherein the activator is a metal alkyl
activator.
11. The method of claim 10, wherein the metal alkyl activator is
triethylaluminum.
12. The method of claim 1, further comprising introducing an
external donor system into a reactor, wherein the external donor
influences the stereoregularity of a resulting polymer.
13. The method of claim 12, wherein the catalyst is pre-contacted
with the external donor system.
14. The method of claim 13, wherein the catalyst and the external
donor system are pre-contacted for less than 10 seconds.
15. The method of claim 12, wherein the activator and electron
donor system are mixed before brought into contact with the
catalyst.
16. The method of claim 1, wherein the catalyst and the catalyst
activator are separately introduced into a catalyst feed conduit
upstream of an injector feeding the catalyst and the catalyst
activator into the reactor.
17. The method of claim 1, wherein the catalyst and the catalyst
activator are separately introduced into the reactor.
18. The method of claim 1, wherein the catalyst is injected into a
first monomer-containing stream and the catalyst activator is
injected into a second monomer-containing stream.
19. The method of claim 2, wherein the catalyst system has a
standard adjusted catalyst activity of greater than 10
gPgcat.sup.-1hr.sup.-1.
20. The method of claim 1, wherein the catalyst system has a
standard adjusted catalyst activity of greater than 40
gPgcat.sup.-1hr.sup.-1.
21. The method of claim 1, wherein the catalyst system has a
standard adjusted catalyst activity of greater than 70
gPgcat.sup.-1hr.sup.-1.
22. The method of claim 1, wherein the catalyst has an aromatic
internal donor.
23. The method of claim 22, wherein the aromatic internal donor is
a phthalate.
24. The method of claim 1, wherein the non-aromatic internal
electron donor comprises a C.sub.1-C.sub.20 diester of a
substituted or unsubstituted C.sub.2-C.sub.10 dicarboxylic
acid.
25. The method of claim 24, wherein the non-aromatic internal
electron donor is a succinate according to the formula:
##STR00003## wherein R.sup.1 and R.sup.2 are independently
C.sub.1-C.sub.20 linear or branched alkyl, alkenyl, or cycloalkyl
hydrocarbyl radicals; and R.sup.3 to R.sup.6 are, independently,
hydrogen, halogen, or C.sub.1-C.sub.20 linear or branched alkyl,
alkenyl, or cycloalkyl hydrocarbyl radicals, wherein the R.sup.3 to
R.sup.6 radicals are not joined together, or wherein at least two
of the R.sup.3 to R.sup.6 radicals are joined to form a cyclic
divalent radical, or a combination thereof.
Description
PRIORITY CLAIMS
[0001] The present application claims priority to and the benefit
of U.S. Ser. No. 61/858,457 filed on Jul. 25, 2013 and EP
Application No. 13185277.4 filed Sep. 20, 2013, the disclosure of
which is hereby incorporated by reference herein in their
entireties.
FIELD OF INVENTION
[0002] This invention relates to polyolefin polymerization and more
particularly to polyolefin polymerization with high activity
catalyst systems.
BACKGROUND OF THE INVENTION
[0003] In many polyolefin polymerization processes, catalyst is
prepared for delivery to the polymerization process by activating
the catalyst solids in a continuous process commonly referred to as
pre-contacting. This pre-contacting step was developed to ensure
that the catalyst solids, such as a Ziegler-Natta "Generation III,
IV or V" catalyst with a titanium polymerization site in its Ti(IV)
state, were activated via an activator, such as a metal alkyl,
e.g., triethylaluminum ("TEA1"), to reduce the titanium
polymerization site to its active Ti(III) state.
[0004] Pre-contacting is often accomplished by introduction of the
catalyst (in the form of catalyst solids) and the activator
(sometimes diluted in an alkane solvent, such as hexane) into a
pre-contacting vessel, where the catalyst and activator are allowed
to mix and react for a pre-contacting time of typically 10 to 20
minutes outside the presence of the olefin monomers. In some
processes, the catalyst is further pre-contacted with an external
donor system to ensure thorough complexation of the external donor
with the active polymerization site to influence the
stereoregularity of the resulting polyolefin. In such cases, the
external donor may be diluted in a solvent, such as mineral oil,
prior to being added to the pre-contacting vessel.
[0005] If the catalyst system is not sufficiently active, low
levels of pre-polymerization are observed during the subsequent
pre-polymerization step. It has been demonstrated that low levels
of pre-polymerization under the mild pre-polymerization conditions
can translate to poor product morphology, such as broken granules,
low bulk density and high fines content. In addition, insufficient
time for external donor complex formation can result in reduced
product crystallinity.
[0006] Injection of the activated catalyst system into the
pre-polymerization reactor has been and continues to become more
challenging as the newer Ziegler-Natta catalyst systems achieve
higher levels of activity. Even under the very mild conditions
where the active catalyst first comes into contact with monomer,
the activity can be high enough to cause polymer formation and
plugging in the injection systems, resulting in reduced reliability
of the production facility and other issues associated with
injector plugging and reactor fouling.
[0007] Most of the reliability improvement development work in this
area has been directed to tempering the reaction conditions at the
point where the active catalyst solids first contact monomer,
including colder injection conditions (e.g., reducing the monomer
feedstream temperature to as low as -20.degree. C. or lower);
higher monomer feedstream flow velocities; or monomer dilution
(e.g., with propane or other inert hydrocarbons). Each of these
solutions has associated disadvantages, including increased
operating costs, lower process efficiency, and reduced catalyst
productivity. It would therefore be desirable to provide a solution
to the problems associated with the use of high-activity catalysts
in such polyolefin polymerization processes while reducing or
eliminating such disadvantages.
SUMMARY OF THE INVENTION
[0008] It has been found that when using high-activity catalyst
systems in polyolefin polymerization processes, suitable catalyst
activity can be achieved with significantly limited or no catalyst
and activator pre-contacting time, thus reducing or avoiding many
of the complications associated with catalyst and activator
pre-contacting, while maintaining the catalyst productivity
capability necessary to ensure adequate levels of
pre-polymerization (to avoid poor product morphology) and good
overall productivity.
[0009] In one aspect, a method is provided for polymerizing an
olefin monomer in a reactor with a highly active polyolefin
polymerization catalyst system. The method includes introducing a
catalyst system comprising a catalyst and a catalyst activator into
the reactor containing the olefin monomer with less than 10 seconds
or no pre-contacting time of the catalyst and the catalyst
activator prior to introducing the catalyst and the catalyst
activator into the reactor. In any embodiment, the catalyst system
may have a standard adjusted catalyst activity of greater than 10
gPgcat.sup.-1hr.sup.-1.
[0010] In another aspect, a method is provided for polyolefin
polymerization. The method includes introducing (i) a Ziegler-Natta
catalyst having a Ti polymerization matrix and an internal electron
donor and (ii) a catalyst activator into a reactor containing an
olefin monomer with less than 10 seconds or no pre-contacting time
of the catalyst and the catalyst activator prior to introducing the
catalyst and catalyst activator in the reactor.
[0011] In yet another aspect, a method is provided for polyolefin
polymerization that includes introducing a catalyst system into a
reactor containing an olefin monomer; wherein the catalyst system
comprises: a catalyst having a titanium polymerization site in a
Ti(IV) state, an activator suitable for reducing the titanium
polymerization site from the Ti(IV) state to an activated Ti(III)
state; and wherein the catalyst and the activator are introduced
into the reactor with less than 10 seconds or no pre-contacting
time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a temperature vs. catalyst activity plot for
two highly active catalyst systems, catalyst systems A and B,
useful in one or more embodiments of the present invention.
[0013] FIG. 2 illustrates a regression curve of catalyst activity
of catalyst system A, a Generation IV Ziegler-Natta catalyst
system.
[0014] FIG. 3 illustrates a regression curve of catalyst activity
catalyst system B, a Generation V Ziegler-Natta catalyst
system.
DETAILED DESCRIPTION OF THE INVENTION
[0015] A method for reliably operating a polyolefin polymerization
process when using high-activity catalyst systems, such as catalyst
system utilizing a Generation IV or later Ziegler-Natta catalyst.
It has been found that suitable catalyst productivity can be
achieved with significantly limited or no catalyst and activator
pre-contacting time, thus reducing or avoiding many of the
complications associated with catalyst and activator
pre-contacting.
[0016] For the purposes of this invention and the claims thereto,
the new numbering scheme for the Periodic Table Groups is used as
in Chem. Eng. News, 1985, 63, 27. Therefore, a "Group 4 metal" is
an element from Group 4 of the Periodic Table.
[0017] The terms "hydrocarbyl radical," "hydrocarbyl" and
"hydrocarbyl group" are used interchangeably throughout this
document unless otherwise specified. For purposes of this
disclosure, a hydrocarbyl radical is defined to be C.sub.1 to
C.sub.20 radicals, or C.sub.1 to C.sub.10 radicals, or C.sub.6 to
C.sub.20 radicals, or C.sub.7 to C.sub.20 radicals that may be
linear, branched, or cyclic where appropriate (aromatic or
non-aromatic); and includes hydrocarbyl radicals substituted with
other hydrocarbyl radicals and/or one or more functional groups
comprising elements from Groups 13-17 of the periodic table of the
elements. In addition, two or more such hydrocarbyl radicals may
together form a fused ring system, including partially or fully
hydrogenated fused ring systems, which may include heterocyclic
radicals.
[0018] The term "substituted" means that a hydrogen atom and/or a
carbon atom in the base structure has been replaced with a
hydrocarbyl radical, and/or a functional group, and/or a heteroatom
or a heteroatom containing group. Accordingly, the term hydrocarbyl
radical includes heteroatom containing groups. For purposes herein,
a heteroatom is defined as any atom other than carbon and hydrogen.
For example, methyl cyclopentadiene (Cp) is a Cp group, which is
the base structure, substituted with a methyl radical, which may
also be referred to as a methyl functional group, ethyl alcohol is
an ethyl group, which is the base structure, substituted with an
--OH functional group, and pyridine is a phenyl group having a
carbon in the base structure of the benzene ring substituted with a
nitrogen atom.
[0019] For purposes herein, unless otherwise stated, a hydrocarbyl
radical may be independently selected from substituted or
unsubstituted methyl, ethyl, ethenyl and isomers of propyl, butyl,
pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,
tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,
nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl,
pentacosyl, hexacosyl, heptacosyl, octacosyl, nonacosyl,
triacontyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl,
octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl,
tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl,
nonadecenyl, eicosenyl, heneicosenyl, docosenyl, tricosenyl,
tetracosenyl, pentacosenyl, hexacosenyl, heptacosenyl, octacosenyl,
nonacosenyl, triacontenyl, propynyl, butynyl, pentynyl, hexynyl,
heptynyl, octynyl, nonynyl, decynyl, undecynyl, dodecynyl,
tridecynyl, tetradecynyl, pentadecynyl, hexadecynyl, heptadecynyl,
octadecynyl, nonadecynyl, eicosynyl, heneicosynyl, docosynyl,
tricosynyl, tetracosynyl, pentacosynyl, hexacosynyl, heptacosynyl,
octacosynyl, nonacosynyl, and triacontynyl.
[0020] For purposes herein, unless otherwise stated, hydrocarbyl
radicals may also include isomers of saturated, partially
unsaturated and aromatic cyclic structures wherein the radical may
additionally be subjected to the types of substitutions described
above. The term "aryl", "aryl radical", and/or "aryl group" refers
to aromatic cyclic structures, which may be substituted with
hydrocarbyl radicals and/or functional groups as defined herein.
Examples of aryl radicals include: acenaphthenyl, acenaphthylenyl,
acridinyl, anthracenyl, benzanthracenyls, benzimidazolyl,
benzisoxazolyl, benzofluoranthenyls, benzofuranyl, benzoperylenyls,
benzopyrenyls, benzothiazolyl, benzothiophenyls, benzoxazolyl,
benzyl, carbazolyl, carbolinyl, chrysenyl, cinnolinyl, coronenyl,
cyclohexyl, cyclohexenyl, methylcyclohexyl, dibenzoanthracenyls,
fluoranthenyl, fluorenyl, furanyl, imidazolyl, indazolyl,
indenopyrenyls, indolyl, indolinyl, isobenzofuranyl, isoindolyl,
isoquinolinyl, isoxazolyl, methyl benzyl, methylphenyl, naphthyl,
oxazolyl, phenanthrenyl, phenyl, purinyl, pyrazinyl, pyrazolyl,
pyrenyl, pyridazinyl, pyridinyl, pyrimidinyl, pyrrolyl,
quinazolinyl, quinolonyl, quinoxalinyl, thiazolyl, thiophenyl, and
the like.
[0021] For purposes herein the term "non-aromatic" refers to
compounds, radicals, and/or functional groups without aromatic
character attributed to cyclic conjugated sp.sup.2 carbons having
protons with a chemical shift relative to TMS consistent with
aromatic protons, or greater than 6, as readily understood by one
of minimal skill in the art.
[0022] It is to be understood that for purposes herein, when a
radical is listed, it indicates that the base structure of the
radical (the radical type) and all other radicals formed when that
radical is subjected to the substitutions defined above. Alkyl,
alkenyl, and alkynyl radicals listed include all isomers including
where appropriate cyclic isomers, for example, butyl includes
n-butyl, 2-methylpropyl, 1-methylpropyl, tert-butyl, and cyclobutyl
(and analogous substituted cyclopropyls); pentyl includes n-pentyl,
cyclopentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,
1-ethylpropyl, and nevopentyl (and analogous substituted
cyclobutyls and cyclopropyls); butenyl includes E and Z forms of
1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl,
1-methyl-2-propenyl, 2-methyl-1-propenyl, and 2-methyl-2-propenyl
(and cyclobutenyls and cyclopropenyls). Cyclic compounds having
substitutions include all isomer forms, for example, methylphenyl
would include ortho-methylphenyl, meta-methylphenyl and
para-methylphenyl; dimethylphenyl would include 2,3-dimethylphenyl,
2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-diphenylmethyl,
3,4-dimethylphenyl, and 3,5-dimethylphenyl.
[0023] Likewise the terms "functional group", "group" and
"substituent" are also used interchangeably throughout this
document unless otherwise specified. For purposes herein, a
functional group includes both organic and inorganic radicals or
moieties comprising elements from Groups 13, 14, 15, 16, and 17 of
the periodic table of elements. Suitable functional groups may
include hydrocarbyl radicals, e.g., alkyl radicals, alkene
radicals, aryl radicals, and/or halogen (Cl, Br, I, F), O, S, Se,
Te, NR*.sub.x, OR*, SeR*, TeR*, PR*.sub.x, AsR*.sub.x, SbR*.sub.x,
SR*, BR*.sub.x, SiR*.sub.x, GeR*.sub.x, SnR*.sub.x, PbR*.sub.x,
and/or the like, wherein R is a C.sub.1 to C.sub.20 hydrocarbyl as
defined above, and wherein x is the appropriate integer to provide
an electron neutral moiety. Other examples of functional groups
include those typically referred to as amines, imides, amides,
ethers, alcohols (hydroxides), sulfides, sulfates, phosphides,
halides, phosphonates, alkoxides, esters, carboxylates, aldehydes,
and the like.
[0024] Polypropylene microstructure is determined by .sup.13C-NMR
spectroscopy, including the concentration of isotactic and
syndiotactic diads ([m] and [r]), triads ([mm] and [rr]), and
pentads ([mmmm] and [rrrr]). The designation "m" or "r" describes
the stereochemistry of pairs of contiguous propylene groups, "m"
referring to meso, and "r" to racemic. Samples are dissolved in
d.sub.2-1,1,2,2-tetrachloroethane, and spectra recorded at
125.degree. C. using a 100 MHz (or higher) NMR spectrometer.
Polymer resonance peaks are referenced to mmmm=21.8 ppm.
Calculations involved in the characterization of polymers by NMR
are described by F. A. Bovey in Polymer Conformation and
Configuration (Academic Press, New York 1969) and J. Randall in
Polymer Sequence Determination, .sup.13C-NMR Method (Academic
Press, New York, 1977).
[0025] For purposes herein, a supported catalyst and/or activator
refers to a catalyst compound, an activator, or a combination
thereof located on, in, or in communication with a support wherein
the activator, the catalyst compound, or a combination thereof are
deposited on, vaporized with, bonded to, incorporated within,
adsorbed or absorbed in, adsorbed or absorbed on, the support.
[0026] For purposes herein an "olefin," alternatively referred to
as "alkene," is a linear, branched, or cyclic compound comprising
carbon and hydrogen having at least one double bond. For purposes
of this specification and the claims appended thereto, when a
polymer or copolymer is referred to as comprising an olefin, the
olefin present in such polymer or copolymer is the polymerized form
of the olefin. For example, when a copolymer is said to have an
"ethylene" content of 35 wt % to 55 wt %, it is understood that the
mer unit in the copolymer is derived from ethylene in the
polymerization reaction and said derived units are present at 35 wt
% to 55 wt %, based upon the weight of the copolymer.
[0027] For purposes herein a "polymer" has two or more of the same
or different "mer" units. A "homopolymer" is a polymer having mer
units that are the same. A "copolymer" is a polymer having two or
more mer units that are different from each other. A "terpolymer"
is a polymer having three mer units that are different from each
other. "Different" in reference to mer units indicates that the mer
units differ from each other by at least one atom or are different
isomerically. Accordingly, the definition of copolymer, as used
herein, includes terpolymers and the like. An oligomer is typically
a polymer having a low molecular weight, such an Mn of less than
25,000 g/mol, or in an embodiment less than 2,500 g/mol, or a low
number of mer units, such as 75 mer units or less. An "ethylene
polymer" or "ethylene copolymer" is a polymer or copolymer
comprising at least 50 mol % ethylene derived units, a "propylene
polymer" or "propylene copolymer" is a polymer or copolymer
comprising at least 50 mol % propylene derived units, and so
on.
[0028] For the purposes of this disclosure, the term
".alpha.-olefin" includes C.sub.2-C.sub.22olefins. Non-limiting
examples of .alpha.-olefins include ethylene, propylene, 1-butene,
1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene,
1-undecene 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene,
1-eicosene, 1-heneicosene, 1-docosene, 1-tricosene, 1-tetracosene,
1-pentacosene, 1-hexacosene, 1-heptacosene, 1-octacosene,
1-nonacosene, 1-triacontene, 4-methyl-1-pentene,
3-methyl-1-pentene, 5-methyl-1-nonene, 3,5,5-trimethyl-1-hexene,
vinylcyclohexane, and vinylnorbornane. Non-limiting examples of
cyclic olefins and diolefins include cyclopropene, cyclobutene,
cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene,
cyclodecene, norbornene, 4-methylnorbornene, 2-methylcyclopentene,
4-methylcyclopentene, vinylcyclohexane, norbornadiene,
dicyclopentadiene, 5-ethylidene-2-norbornene, vinylcyclohexene,
5-vinyl-2-norbornene, 1,3-divinylcyclopentane,
1,2-divinylcyclohexane, 1,3-divinylcyclohexane,
1,4-divinylcyclohexane, 1,5-divinylcyclooctane,
1-allyl-4-vinylcyclohexane, 1,4-diallylcyclohexane,
1-allyl-5-vinylcyclooctane, and 1,5-diallylcyclooctane.
[0029] The terms "catalyst" and "catalyst compound" are defined to
mean a compound capable of initiating polymerization catalysis
under the appropriate conditions. In the description herein, the
catalyst may be described as a catalyst precursor, a pre-catalyst
compound, or a transition metal compound, and these terms are used
interchangeably. A catalyst compound may be used by itself to
initiate catalysis or may be used in combination with an activator,
an internal electron donor, one or more external electron donors,
and/or a co-catalyst to initiate catalysis. When the catalyst
compound is combined with electron donors and/or co-catalysts to
initiate catalysis, the catalyst compound is often referred to as a
pre-catalyst or catalyst precursor. A "catalyst system" is a
combination of at least one catalyst compound, at least one
internal electron donor, one or more external electron donors, a
co-catalyst, and/or a support where the system can polymerize
monomers to produce a polymer under polymerization conditions of
suitable temperature and pressure.
[0030] For purposes herein the term "catalyst activity" is a
measure of how many grams of polymer (P) are produced using a
polymerization catalyst comprising (W) grams of catalyst (cat),
over a period of time of (T) equal to 1 hour measured from the
initiation of catalytic polymerization; and may be expressed by the
following formula: P/(T.times.W) and expressed in units of
gPgcat.sup.-1hr.sup.-1. "Conversion" is the amount of monomer that
is converted to polymer product, and is reported as wt % and is
calculated based on the polymer yield and the amount of monomer fed
into the reactor. Because the activity of a catalyst system can be
affected by reactor temperature and catalyst-activator
pre-contacting conditions, the term "standard adjusted catalyst
activity" as used herein refers to a catalyst system's activity
under the following standard conditions: (a) catalyst and activator
are mixed and allowed to pre-contact for a period of time of at
least 10 minutes, and (b) catalyst and activator are injected into
a reactor having a monomer feedstream temperature of 5.degree. C.
at the injection point. It should be appreciated that "standard
adjusted catalyst activity" therefore is a standardized measure of
a given catalyst system's activity under defined conditions and is
not intended to imply or require that the referenced catalyst
system actually be employed in a process under such conditions. For
example, reference may be made to a catalyst's "standard adjusted
catalyst activity" even where the catalyst is used in a process
where there is no pre-contacting of catalyst and activator or where
pre-contacting time is limited to 10 seconds or less or where the
reactor is operated at a different temperature at the catalyst
injection point. In certain embodiments, the methods disclosed
herein advantageously may be employed with catalyst systems having
high standard adjusted catalyst activity. Thus, standard adjusted
catalyst activity as defined herein is a helpful catalyst property
for identifying certain catalyst systems useful in the methods
disclosed herein.
[0031] A "scavenger" is a compound that is typically added to
facilitate oligomerization or polymerization by scavenging
impurities. Some scavengers may also act as activators and may be
referred to as co-activators. A co-activator, that is not a
scavenger, may also be used in conjunction with an activator in
order to form a catalyst system. In an embodiment, a co-activator
can be pre-mixed with the catalyst compound to form an alkylated
catalyst compound.
[0032] A "propylene polymer" or "polypropylene" is a polymer having
at least 50 mol % of propylene. As used herein, Mn is number
average molecular weight as determined by proton nuclear magnetic
resonance spectroscopy (.sup.1H NMR) or by gel permeation
chromatography (GPC) unless stated otherwise, Mw is weight average
molecular weight determined by gel permeation chromatography (GPC),
and Mz is z average molecular weight determined by GPC, wt % is
weight percent, and mol % is mole percent. Molecular weight
distribution (MWD) is defined to be Mw divided by Mn. Unless
otherwise noted, all molecular weight units, e.g., Mw, Mn, Mz, are
g/mol.
[0033] The following abbreviations may be used through this
specification: Me is methyl, Ph is phenyl, Et is ethyl, Pr is
propyl, iPr is isopropyl, n-Pr is normal propyl, Bu is butyl,
iso-butyl is isobutyl, sec-butyl refers to secondary butyl,
tert-butyl, refers to tertiary butyl, n-butyl is normal butyl, pMe
is para-methyl, Bz is benzyl, THF is tetrahydrofuran, Mes is
mesityl, also known as 1,3,5-trimethylbenzene, Tol is toluene, TMS
is trimethylsilyl, and MAO is methylalumoxane. For purposes herein,
"RT" is room temperature, which is defined as 25.degree. C. unless
otherwise specified. All percentages are in weight percent (wt %)
unless otherwise specified.
[0034] For purposes herein, Mw, Mz number of carbon atoms, g value
and g'.sub.vis may be determined by using a High Temperature Size
Exclusion Chromatograph (either from Waters Corporation or Polymer
Laboratories), equipped with three in-line detectors, a
differential refractive index detector (DRI), a light scattering
(LS) detector, and a viscometer. Experimental details, including
detector calibration, are described in: T. Sun, P. Brant, R. R.
Chance, and W. W. Graessley, Macromolecules, Volume 34, Number 19,
6812-6820, (2001), and references therein. Three Polymer
Laboratories PLgel 10 mm Mixed-B LS columns are used. The nominal
flow rate is 0.5 cm.sup.3/min, and the nominal injection volume is
300 .mu.L. The various transfer lines, columns and differential
refractometer (the DRI detector) are contained in an oven
maintained at 145.degree. C. Solvent for the experiment is prepared
by dissolving 6 grams of butylated hydroxy toluene as an
antioxidant in 4 liters of Aldrich reagent grade 1, 2, 4
trichlorobenzene (TCB). The TCB mixture is then filtered through a
0.7 .mu.m glass pre-filter and subsequently through a 0.1 .mu.m
Teflon filter. The TCB is then degassed with an online degasser
before entering the Size Exclusion Chromatograph. Polymer solutions
are prepared by placing dry polymer in a glass container, adding
the is desired amount of TCB, then heating the mixture at
160.degree. C. with continuous agitation for about 2 hours. All
quantities are measured gravimetrically. The TCB densities used to
express the polymer concentration in mass/volume units are 1.463
g/ml at room temperature and 1.324 g/ml at 145.degree. C. The
injection concentration is from 0.75 to 2.0 mg/ml, with lower
concentrations being used for higher molecular weight samples.
Prior to running each sample the DRI detector and the injector are
purged. Flow rate in the apparatus is then increased to 0.5
ml/minute, and the DRI is allowed to stabilize for 8 to 9 hours
before injecting the first sample. The LS laser is turned on 1 to
1.5 hours before running the samples. The concentration, c, at each
point in the chromatogram is calculated from the
baseline-subtracted DRI signal, I.sub.DRI, using the following
equation:
c=K.sub.DRII.sub.DRI/(dn/dc)
[0035] where K.sub.DRI is a constant determined by calibrating the
DRI, and (dn/dc) is the refractive index increment for the system.
The refractive index, n=1.500 for TCB at 145.degree. C. and
.lamda.=690 nm. For purposes of this invention and the claims
thereto (dn/dc)=0.104 for propylene polymers, 0.098 for butene
polymers and 0.1 otherwise. Units on parameters throughout this
description of the SEC method are such that concentration is
expressed in g/cm.sup.3, molecular weight is expressed in g/mol,
and intrinsic viscosity is expressed in dL/g.
[0036] The LS detector is a Wyatt Technology High Temperature
mini-DAWN. The molecular weight, M, at each point in the
chromatogram is determined by analyzing the LS output using the
Zimm model for static light scattering (M. B. Huglin, LIGHT
SCATTERING FROM POLYMER SOLUTIONS, Academic Press, 1971):
K o c .DELTA. R ( .theta. ) = 1 MP ( .theta. ) + 2 A 2 c
##EQU00001##
[0037] Here, .DELTA.R(.theta.) is the measured excess Rayleigh
scattering intensity at scattering angle .theta., c is the polymer
concentration determined from the DRI analysis, A.sub.2 is the
second virial coefficient [for purposes of this invention,
A.sub.2=0.0006 for propylene polymers, 0.0015 for butene polymers
and 0.001 otherwise], (dn/dc)=0.104 for propylene polymers, 0.098
for butene polymers, and 0.1 otherwise, P(.theta.) is the form
factor for a monodisperse random coil, and K.sub.o is the optical
constant for the system:
K o = 4 .pi. 2 n 2 ( dn / dc ) 2 .lamda. 4 N A ##EQU00002##
[0038] where N.sub.A is Avogadro's number, and (dn/dc) is the
refractive index increment for the system. The refractive index,
n=1.500 for TCB at 145.degree. C. and =690 nm.
[0039] A high temperature Viscotek Corporation viscometer, which
has four capillaries arranged in a Wheatstone bridge configuration
with two pressure transducers, is used to determine specific
viscosity. One transducer measures the total pressure drop across
the detector, and the other, positioned between the two sides of
the bridge, measures a differential pressure. The specific
viscosity, .eta..sub.s, for the solution flowing through the
viscometer is calculated from their outputs. The intrinsic
viscosity, [.eta.], at each point in the chromatogram is calculated
from the following equation:
.eta..sub.s=c[.eta.]+0.3(c[.eta.]).sup.2
[0040] where c is concentration and was determined from the DRI
output.
[0041] The branching index (g'.sub.vis) is calculated using the
output of the SEC-DRI-LS-VIS method as follows. The average
intrinsic viscosity, [.eta.].sub.avg, of the sample is calculated
by:
[ .eta. ] avg = c i [ .eta. ] i c i ##EQU00003##
[0042] where the summations are over the chromatographic slices, i,
between the integration limits. The branching index g'.sub.vis,
which is also referred to simply as g' is defined as:
g ' vis = [ .eta. ] avg kM v .alpha. ##EQU00004##
[0043] where, for purpose of this invention and claims thereto,
.alpha.=0.695 and k=0.000579 for linear ethylene polymers,
.alpha.=0.705 and k=0.000262 for linear propylene polymers, and
.alpha.=0.695 and k=0.000181 for linear butene polymers. M.sub.v is
the viscosity-average molecular weight based on molecular weights
determined by LS analysis.
[0044] The term "g" also called a "g value" is defined to be
Rg.sup.2.sub.pm/Rg.sup.2.sub.ls, where Rg.sub.pm is the radius of
gyration for the polymacromer, Rg.sup.2.sub.ls is the radius of
gyration for the linear standard, and Rg.sub.ls=K.sub.sM.sup.0.58
where K.sub.s is the power law coefficient (0.023 for linear
polyethylene, 0.0171 for linear polypropylene, and 0.0145 for
linear polybutene), and M is the molecular weight as described
above, Rg.sub.pm=K.sub.TM.sup..alpha.s. .alpha..sub.s is the size
coefficient for the polymacromer, K.sub.T is the power law
coefficient for the polymacromer. See Macromolecules, 2001, 34,
6812-6820, for guidance on selecting a linear standard having the
molecular weight and comonomer content, and determining K
coefficients and a exponents.
Process
[0045] Disclosed herein are methods for reliably operating a
polyolefin polymerization process when using high-activity catalyst
systems, such as a catalyst system utilizing a Generation IV or
subsequent (e.g., Generation IV, V, VI, and so on) Ziegler-Natta
catalyst or is other highly active catalyst systems, including
metallocene catalyst systems. It has been found that suitable
catalyst activity can be achieved with significantly limited or no
catalyst and activator pre-contacting time, thus reducing or
avoiding many of the complications associated with catalyst and
activator pre-contacting. Various catalyst and activator injection
schemes may be employed to eliminate or limit the pre-contacting
time, and several general schemes are described in greater detail
herein.
[0046] In any embodiment, the process can be used in the
polymerization of propylene polymers, including propylene-based
homopolymers and copolymers. For example, the process can be used
in the polymerization of propylene copolymers where a majority of
the mer units are derived from propylene and other mer units are
derived from ethylene or a C.sub.4-C.sub.10olefin. It is
contemplated, however, that the process can be used for any
polyolefin polymerization process in which catalyzed polymerization
is performed with similarly highly-active catalyst systems.
[0047] In any embodiment, the inventive method may include
introducing a catalyst and an activator into a reactor wherein the
catalyst and the activator are introduced into the reactor with
less than 10 seconds or no pre-contacting time. The reactor may be
a vessel in which one or more olefin monomers are present. For
example, the reactor may be a pre-polymerization reactor or a
primary polymerization reactor. In any embodiment, the reactor may
be a slurry loop reactor.
[0048] In any embodiment, the method may further include
introducing an external donor system into the reactor. The external
donor may be a compound that influences the stereoregularity of a
resulting polymer. Various non-limiting examples of external donors
that may be employed in the process are described subsequently
herein. In any embodiment, the catalyst may be pre-contacted with
the external donor system before being introduced into the reactor.
For example, the catalyst may be pre-contacted with the external
donor system for a period of time of less than 10 seconds, or less
than 5 seconds. Alternatively, in other embodiments, the catalyst
and external donor system may be introduced separately into the
reactor. In any embodiment, the activator and electron donor system
may be mixed before being brought into contact with the
catalyst.
[0049] The catalyst and catalyst activator may be introduced into
the process at various locations to avoid or limit pre-contacting
time between the catalyst and activator. For example, in any
embodiment, the catalyst and the catalyst activator may be
separately introduced into a catalyst feed conduit upstream of an
injector feeding the catalyst and the catalyst activator into the
reactor. In an alternate embodiment, the catalyst and the catalyst
activator may be separately introduced into the reactor. In an
exemplary embodiment, the catalyst may be injected into a first
monomer-containing stream and the catalyst activator is injected
into a second monomer-containing stream.
[0050] In any embodiment, the catalyst may be injected in a
monomer-containing stream upstream of an injection point where the
catalyst activator is injected. In any embodiment, the catalyst
activator and external electron donor may be premixed and
optionally cooled before being injected into the monomer-containing
stream. In any embodiment, the catalyst may be injected into a
first monomer stream and the catalyst activator and external
electron donor may be injected into a second monomer stream. The
introduction of catalyst system components into the reactor may be
any injector known in the art to effectively inject a catalyst
solid slurry into a monomer-containing system.
[0051] In any embodiment, pre-contacting time may be controlled by
independently adjusting the flow rate of any of the catalyst system
components. For example, pre-contacting time may be controlled by
independently adjusting the flow rate of the catalyst activator.
Pre-contacting time may also be controlled by injecting and/or
adjusting the flow rate of an inert component. For example, the
inert component may be a C.sub.3-C.sub.50alkane. In any embodiment,
the inert may be selected from the group consisting of: propane,
butane, pentane, hexane, mineral oil, and combinations thereof. In
an exemplary embodiment, the inert component may comprise a mineral
oil and, optionally, a petroleum grease.
[0052] The methods for limiting or avoiding catalyst and activator
pre-contacting described herein may be advantageously employed with
a highly active catalyst system used in a polymerization process to
produce a polypropylene resin comprising at least 50 mol %
propylene, an MWD greater than about 5 and a melt strength of at
least 20 cN determined using an extensional rheometer at
190.degree. C., the catalyst system comprising: a Ziegler-Natta
catalyst comprising a non-aromatic internal electron donor; and
first and second external electron donors comprising different
organosilicon compounds. In any embodiment, the first external
electron donor may have the formula
R.sup.1.sub.2Si(OR.sup.2).sub.2, wherein each R.sup.1 is
independently a hydrocarbyl radical comprising from 1 to 10 carbon
atoms in which the carbon adjacent to the Si is a secondary or a
tertiary carbon atom, and wherein each R.sup.2 is independently a
hydrocarbyl radical comprising from 1 to 10 carbon atoms; and the
second external electron donor has the formula
R.sup.3.sub.nSi(OR.sup.4).sub.4-n, wherein each R.sup.3 and R.sup.4
are independently a hydrocarbyl radical comprising from 1 to 10
carbon atoms, n is 1, 2, or 3, and the second external electron
donor is different than the first external electron donor.
[0053] In any embodiment, the non-aromatic internal electron donor
may comprise an aliphatic amine, amide, ester, ether, ketone,
nitrile, phosphine, phosphoramide, thioether, thioester, aldehyde,
alcoholate, carboxylic acid, or a combination thereof, or a
C.sub.1-C.sub.20 diester of a substituted or unsubstituted
C.sub.2-C.sub.10 dicarboxylic acid, or a succinate according to the
formula:
##STR00001##
[0054] wherein R.sup.1 and R.sup.2 are, independently,
C.sub.1-C.sub.20 linear or branched alkyl, alkenyl, or cycloalkyl
hydrocarbyl radicals; R.sup.3 to R.sup.6 are, independently,
hydrogen, halogen, or C.sub.1-C.sub.20 linear or branched alkyl,
alkenyl, or cycloalkyl hydrocarbyl radicals, wherein the R.sup.3 to
R.sup.6 radicals are not joined together, or wherein at least two
of the R.sup.3 to R.sup.6 radicals are joined to form a cyclic
divalent radical, or a combination thereof.
[0055] In any embodiment, the polymerization process according to
the instant disclosure may include contacting propylene with any
embodiment herein described of the catalyst system under
polymerization conditions. In any embodiment, the polymerization
process may include a preliminary polymerization step. In any
embodiment, the preliminary polymerization may include utilizing
the Ziegler-Natta catalyst system comprising the non-aromatic
internal electron donor in combination with at least a portion of
the organoaluminum co-catalyst wherein at least a portion of the
external electron donors are present wherein the catalyst system is
utilized in a higher concentration than utilized in the subsequent
"main" polymerization process.
[0056] In any embodiment, the concentration of the catalyst system
in the preliminary polymerization, based on the moles of titanium
present, may be about 0.01 to 200 millimoles, or about 0.05 to 100
millimoles, calculated as a titanium atom, per liter of an inert
hydrocarbon medium. In any embodiment, the organoaluminum
co-catalyst may be present in an amount sufficient to produce about
0.1 to 500 g, or 0.3 to 300 g, of a polymer per gram of the
titanium catalyst present, and may be present at about 0.1 to 100
moles, or about 0.5 to 50 moles, per mole of the titanium atom
present in the catalyst component.
[0057] In any embodiment, the preliminary polymerization may be
carried out under mild conditions in an inert hydrocarbon medium in
which an olefin and the catalyst components are present. Examples
of the inert hydrocarbon medium used include aliphatic
hydrocarbons, such as propane, butane, pentane, hexane, heptane,
octane, decane, dodecane and kerosene; alicyclic hydrocarbons, such
as cyclopentane, cyclohexane and methylcyclopentane; aromatic
hydrocarbons, such as benzene, toluene and xylene; halogenated
hydrocarbons, such as ethylene chloride and chlorobenzene; and
mixtures thereof. The olefin used in the preliminary polymerization
may be the same as an olefin to be used in the main
polymerization.
[0058] In any embodiment, the reaction temperature for the
preliminary polymerization may be a point at which the resulting
preliminary polymerization does not dissolve substantially in the
inert hydrocarbon medium, which may be about -20 to +100.degree.
C., or about -20 to +80.degree. C., or from 0 to 40.degree. C.
[0059] In any embodiment, during the preliminary polymerization, a
molecular weight controlling agent such as hydrogen may be used.
The molecular weight controlling agent may desirably be used in
such an amount that the polymer obtained by preliminary
polymerization has properties consistent with the intended product.
In any embodiment, the preliminary polymerization may be carried
out so that about 0.1 to 1000 g, or about 0.3 to 300 g, of a
polymer forms per gram of the titanium catalyst.
[0060] The methods for limiting or avoiding catalyst and activator
pre-contacting described herein may be advantageously employed with
a highly active catalyst system used in a polymerization process
for producing a polypropylene resin, wherein the process comprises
contacting propylene monomers at a temperature and a pressure in
the presence of catalyst system to produce a propylene resin
comprising at least 50 mol % propylene, and wherein the catalyst
system comprises:
[0061] a Ziegler-Natta catalyst comprising a non-aromatic internal
electron donor;
[0062] a first external electron donor having the formula
R.sup.1.sub.2Si(OR.sup.2).sub.2, wherein each R.sup.1 is
independently a hydrocarbyl radical comprising from 1 to 10 carbon
atoms in which the carbon adjacent to the Si is a secondary or a
tertiary carbon atom, and wherein each R.sup.2 is independently a
hydrocarbyl radical comprising from 1 to 10 carbon atoms; and
[0063] a second external electron donor having the formula
R.sup.3.sub.nSi(OR.sup.4).sub.4-n,
[0064] wherein each R.sup.3 and R.sup.4 are independently a
hydrocarbyl radical comprising from 1 to 10 carbon atoms,
[0065] n is 1, 2, or 3; and
[0066] the second external electron donor is different than the
first external electron donor.
[0067] In any embodiment, the propylene polymer resin may have a
melt strength of at least 20 cN determined using an extensional
rheometer at 190.degree. C.
[0068] In any embodiment, the olefin may comprise or consist
essentially of propylene. In any embodiment, the olefin may
comprise from 0 to 49% of an alpha olefin other than propylene, as
defined herein. In any embodiment, the alpha olefin may include
ethylene, 1-butene, 4-methyl-1-pentene, 1-octene, or a combination
thereof. In any embodiment, the olefin may comprise at least 50 wt
% propylene, or at least 75 wt %, or at least 99 wt %
propylene.
[0069] In any embodiment, the polymerization of the olefin may be
carried out in the gaseous phase, the liquid phase, bulk phase,
slurry phase, or any combination thereof.
[0070] In any embodiment, polymerization may be carried out by
slurry polymerization wherein the inert hydrocarbon may be used as
a reaction solvent, or an olefin liquid under the reaction
conditions may be used as the solvent.
[0071] In any embodiment, the titanium catalyst may be present in
the reactor at about 0.005 to 0.5 millimole, preferably about 0.01
to 0.5 millimole, based on Ti moles per liter of the reaction zone.
In any embodiment, the organoaluminum co-catalyst may be present in
an amount sufficient to produce about 1 to 2,000 moles, or about 5
to 500 moles of aluminum per mole of the titanium atom in the
catalyst system. In any embodiment, the internal electron donor may
be present at about 0.2 to about 5.0, or about 0.5 to about 2.0 per
mole of Ti.
[0072] In any embodiment, the total amount of the external electron
donors may be about 0.001 to 50 moles, or about 0.01 to 20 moles,
or about 0.05 to 10 mole Si per mole of Ti present.
[0073] In any embodiment, the first external electron donor may be
present in the catalyst system at from about 2.5 to 50 mol %, or
about 2.5 to 10 mol % of the total amount of external electron
donor present.
[0074] In any embodiment, the polymerization process may include
contacting the titanium catalyst component, the organoaluminum
co-catalyst, and the two external electron donors with each other
at the time of the main polymerization, before the main
polymerization, for example, at the time of the preliminary
polymerization, or a combination thereof. In contacting them before
the main polymerization, any two or more of these components may be
freely selected and contacted. In any embodiment, two or more of
the components may be contacted individually or partly and then
contacted with each other in total to produce the catalyst
system.
[0075] In any embodiment, the catalyst system components may be
contacted with each other before the polymerization in an inert
gaseous atmosphere, the individual catalyst components may be
contacted with each other in an olefin atmosphere, or any
combination thereof.
[0076] In any embodiment, hydrogen may be used during the
polymerization to control the molecular weight and other properties
of the resulting polymer.
[0077] In any embodiment, polymerization conditions may include a
polymerization temperature of about 20 to 200.degree. C., or about
50 to 180.degree. C., and a pressure from atmospheric pressure to
about 100 kg/cm.sup.2, or from about 2 to 50 kg/cm.sup.2. The
polymerization process according to the instant disclosure may be
carried out batchwise, semicontinuously, or continuously. The
polymerization may be carried out in two or more stages, using two
or more reactors under different reaction conditions, utilizing
different internal electron donors, different external electron
donors, and/or different catalyst systems.
[0078] In any embodiment, the polypropylene resin according to the
instant disclosure may be produced in a bulk continuous reactor. A
catalyst system comprising a magnesium chloride supported titanium
catalyst according to one or more embodiments of the instant
disclosure is utilized. Catalyst preparation may be carried out
continuously in situ by contacting the catalyst solids,
triethylaluminum, and the external electron donor system under
conditions known in the art to yield active, stereospecific
catalyst for polymerization of propylene. The activated catalyst
may then be continuously fed into a prepolymerization reactor where
it is continuously polymerized in propylene to a productivity of
approximately 100 to 400 g-polymer/g-cat. The prepolymerized
catalyst may then be continuously fed into a bulk slurry reactor,
and polymerization continued at 70.degree. C. to 80.degree. C., for
a residence time of about 90 minutes. The reaction slurry
(homopolymer granules in bulk propylene) may then be removed from
the reactor and the polymer granules continuously separated from
the liquid propylene. The polymer granules may then be separated
from the unreacted monomer to produce a granular product for
compounding and/or mechanical properties. In any embodiment,
hydrogen may be used in the reactor to control the melt flow rate
of the polypropylene resin.
[0079] In the case of impact copolymer resin production, the
granules from the bulk reactor, after removing the monomer, may be
fed directly into a Gas Phase Reactor (GPR) where polymerization is
continued under conditions known in the art to produce
ethylene-propylene bipolymer within the pores of the polymer
granules. The final product, referred to in the art as an "impact
copolymer," may be continuously withdrawn from the gas phase
reactor and separated from unreacted monomer to produce a granular
product for compounding and further processing. The molecular
weight of the ethylene-propylene rubber or more appropriately,
Intrinsic Viscosity (IV) of the rubber phase may be controlled by
the concentration of hydrogen in the GPR.
[0080] In any embodiment, the granules from the reactor may be
stabilized with at least 0.01 wt % of an additive, e.g., 0.15 wt %
Irganox.TM. 1010, 0.05 wt % Ultranox.TM. 626A, and/or with 0.075 wt
% sodium benzoate (fine form) and then pelletized, e.g., on a 30 mm
Werner & Pfleiderer twin screw extruder. The pellets may then
be injection molded, and/or subjected to further processing.
Catalyst Systems
[0081] The methods for reliably operating a polyolefin
polymerization process described herein are particularly
well-suited for catalyst systems having a high activity. It has
been found that suitable catalyst activity can be achieved with
significantly limited or no catalyst and activator pre-contacting
time, thus reducing or avoiding many of the complications
associated with catalyst and activator pre-contacting.
[0082] More particularly, the methods may be advantageously
employed with catalyst systems having a standard adjusted catalyst
activity of greater than 10 gPgcat.sup.-1hr.sup.-1, particularly
greater than 40 gPgcat.sup.-1hr.sup.-1, and even more particularly
catalyst systems having a standard adjusted catalyst activity of
greater than 70 gPgcat.sup.-1hr.sup.-1, including catalyst systems
having a catalyst activity of greater than 160
gPgcat.sup.-1hr.sup.-1.
[0083] Of particular interest are highly active Ziegler-Natta
catalyst systems, particularly catalysts comprising a Ti
polymerization site and internal electronic donor(s), such as in
Generation IV or later Ziegler-Natta catalysts (e.g., Generation
IV, V and subsequent catalyst systems). Subsequent generation
Ziegler-Natta catalysts generally have higher activity than
previous generation Ziegler-Natta catalysts.
[0084] In any embodiment, Ziegler-Natta catalysts suitable for use
herein include solid titanium supported catalyst systems described
in U.S. Pat. Nos. 4,990,479 and 5,159,021, and PCT Publication No.
WO 00/63261, and others. Briefly, the Ziegler-Natta catalyst can be
obtained by: (1) suspending a dialkoxy magnesium compound in an
aromatic hydrocarbon that is liquid at ambient temperatures; (2)
contacting the dialkoxy magnesium hydrocarbon composition with a
titanium halide and with a diester of an aromatic dicarboxylic
acid; and (3) contacting the resulting functionalized dialkoxy
magnesium-hydrocarbon composition of step (2) with additional
titanium halide.
[0085] In any embodiment, the catalyst system may be a solid
titanium catalyst component comprising magnesium, titanium,
halogen, a non-aromatic internal electron donor, and two or more
external electron donors. The solid titanium catalyst component,
also referred to as a Ziegler-Natta catalyst, can be prepared by
contacting a magnesium compound, a titanium compound, and at least
the internal electron donor. Examples of the titanium compound used
in the preparation of the solid titanium catalyst component include
tetravalent titanium compounds having the formula:
Ti(OR.sub.n)X.sub.4-n
wherein R is a hydrocarbyl radical, X is a halogen atom, and n is
from 0 to 4.
[0086] In any embodiment, suitable titanium compounds for use
herein include: titanium tetra-halides such as TiCl.sub.4,
TiBr.sub.4, and/or TiI.sub.4; alkoxy titanium trihalides including
Ti(OCH.sub.3)Cl.sub.3, Ti(OC.sub.2H.sub.5)Cl.sub.3, Ti(O
n-C.sub.4H.sub.9)Cl.sub.3, Ti(OC.sub.2H.sub.5)Br.sub.3, and/or
Ti(.beta. iso-C.sub.4H.sub.9)Br.sub.3; dialkoxytitanium dihalides
including Ti(OCH.sub.3).sub.2Cl.sub.2,
Ti(OC.sub.2H.sub.5).sub.2Cl.sub.2, Ti(O
n-C.sub.4H.sub.9).sub.2Cl.sub.2, and/or
Ti(OC.sub.2H.sub.5).sub.2Br.sub.2; trialkoxytitanium monohalides
including Ti(OCH.sub.3).sub.3Cl, Ti(OC.sub.2H.sub.5).sub.3Cl, Ti(O
n-C.sub.4H.sub.9).sub.3Cl, and/or Ti(OC.sub.2H.sub.5).sub.3Br;
and/or tetraalkoxy titaniums including Ti(OCH.sub.3).sub.4,
Ti(OC.sub.2H.sub.5).sub.4, and/or Ti(O n-C.sub.4H.sub.9).sub.4.
[0087] In any embodiment, the halogen-containing titanium compound
may be a titanium tetrahalide, or titanium tetrachloride. The
titanium compounds may be used singly or in combination with each
other. The titanium compound may be diluted with a hydrocarbon
compound or a halogenated hydrocarbon compound.
[0088] In any embodiment, the magnesium compound to be used in the
preparation of the solid titanium catalyst component may include a
magnesium compound having reducibility and/or a magnesium compound
having no reducibility. Suitable magnesium compounds having
reducibility may, for example, be magnesium compounds having a
magnesium-carbon bond or a magnesium-hydrogen bond. Suitable
examples of such reducible magnesium compounds include dimethyl
magnesium, diethyl magnesium, dipropyl magnesium, dibutyl
magnesium, diamyl magnesium, dihexyl magnesium, didecyl magnesium,
magnesium ethyl chloride, magnesium propyl chloride, magnesium
butyl chloride, magnesium hexyl chloride, magnesium amyl chloride,
butyl ethoxy magnesium, ethyl butyl magnesium, and/or butyl
magnesium halides. These magnesium compounds may be used singly or
they may form complexes with the organoaluminum co-catalyst as
described herein. These magnesium compounds may be a liquid or a
solid.
[0089] Suitable examples of the magnesium compounds having no
reducibility include magnesium halides such as magnesium chloride,
magnesium bromide, magnesium iodide, and magnesium fluoride; alkoxy
magnesium halides, such as magnesium methoxy chloride, magnesium
ethoxy chloride, magnesium isopropoxy chloride, magnesium phenoxy
chloride, and magnesium methylphenoxy chloride; alkoxy magnesiums,
such as ethoxy magnesium, isopropoxy magnesium, butoxy magnesium,
n-octoxy magnesium, and 2-ethylhexoxy magnesium; aryloxy magnesiums
such as phenoxy magnesium and dimethylphenoxy magnesium; and/or
magnesium carboxylates, such as magnesium laurate and magnesium
stearate.
[0090] In any embodiment, non-reducible magnesium compounds may be
compounds derived from the magnesium compounds having reducibility,
or may be compounds derived at the time of preparing the catalyst
component. The magnesium compounds having no reducibility may be
derived from the compounds having reducibility by, for example,
contacting the magnesium compounds having reducibility with
polysiloxane compounds, halogen-containing silane compounds,
halogen-containing aluminum compounds, esters, alcohols, and the
like.
[0091] In any embodiment, the magnesium compounds having
reducibility and/or the magnesium compounds having no reducibility
may be complexes of the above magnesium compounds with other
metals, or mixtures thereof with other metal compounds. They may
also be mixtures of two or more types of the above compounds. In
any embodiment, halogen-containing magnesium compounds, including
magnesium chloride, alkoxy magnesium chlorides and aryloxy
magnesium chlorides may be used.
[0092] In any embodiment, a suitable solid catalyst component
comprising a non-aromatic internal electron donor may be a catalyst
solid sold by Lyondell-Basell Inc. under the trade name of
Avant.TM. ZN-168. Such a catalyst is used to exemplify the
invention, other titanium supported catalyst systems are
contemplated. Other catalyst use mechanisms are contemplated.
Including, but not limited to, batch prepolymerization, in situ
prepolymerization and other such mechanisms.
Activators
[0093] In any embodiment, supported Ziegler-Natta catalysts may be
used in combination with an activator, also referred to herein as a
co-catalyst. In any embodiment, compounds containing at least one
aluminum-carbon bond in the molecule may be utilized as the
co-catalysts, also referred to herein as an organoaluminum
co-catalyst. Suitable organoaluminum compounds include
organoaluminum compounds of the general formula:
R.sup.1.sub.mAl(OR.sup.2).sub.nH.sub.pX.sub.q
wherein R.sup.1 and R.sup.2 are identical or different, and each
represents a hydrocarbyl radical containing from 1 to 15 carbon
atoms, or 1 to 4 carbon atoms; X represents a halogen atom; and
0<m.ltoreq.3, 0.ltoreq.n<3, 0.ltoreq.p<3, and
0.ltoreq.q<3, and m+n+p+q=3.
[0094] Other suitable organoaluminum compounds include complex
alkylated compounds of metals of Group I and aluminum represented
by the general formula:
M.sup.1AlR.sup.1.sub.4
wherein M.sup.1 is Li, Na, or K and R.sup.1 is as defined
above.
[0095] Suitable organoaluminum compounds include compounds
represented by the following general formulae:
R.sup.1.sub.mAl(OR.sup.2).sub.3-m
wherein R.sup.1 and R.sup.2 are as defined above, and m is
preferably 1.5.ltoreq.m.ltoreq.3;
R.sup.1.sub.mAl(H).sub.3-m
wherein R.sup.1 is as defined above, X is halogen, and m is
0<m<3, or 2.ltoreq.m<3; and/or
R.sup.1.sub.mAl(OR.sup.2).sub.nX.sub.q
wherein R.sup.1 and R.sup.2 are as defined above, X is halogen,
0<m.ltoreq.3, 0.ltoreq.n<3, 0.ltoreq.q<3, and m+n+q=3.
[0096] Suitable examples of the organoaluminum compounds include
trialkyl aluminums such as trimethyl aluminum, triethyl aluminum
and tributyl aluminum; trialkenyl aluminums such as triisoprenyl
aluminum; dialkyl aluminum alkoxides such as diethyl aluminum
ethoxide and dibutyl aluminum ethoxide; alkyl aluminum
sesquialkoxides such as ethyl aluminum sesquiethoxide and butyl
aluminum sesqui-butoxide; partially alkoxylated alkyl aluminums
having an average composition represented by the general formula
R.sup.1.sub.2.5Al(OR.sup.2).sub.0.5; partially halogenated alkyl
aluminums, for example, alkyl aluminum dihalides such as ethyl
aluminum dichloride, propyl aluminum dichloride and butyl aluminum
dibromide; partially hydrogenated alkyl aluminums, for example,
alkyl aluminum dihydrides such as ethyl aluminum dihydride and
propyl aluminum dihydride; and partially alkoxylated and
halogenated alkyl aluminums such as ethyl aluminum ethoxychloride,
butyl aluminum butoxychloride, and ethyl aluminum
ethoxybromide.
[0097] In any embodiment, the organoaluminum compound may comprise
two or more aluminum atoms bonded through an oxygen or nitrogen
atom. Examples include
(C.sub.2H.sub.5).sub.2AlOAl(C.sub.2H.sub.5).sub.2,
(C.sub.4H.sub.9).sub.2AlOAl(C.sub.4H.sub.9).sub.2, and/or
methylaluminoxane (MAO). Other suitable examples include
LiAl(C.sub.2H.sub.5).sub.4 and LiAl(C.sub.2H.sub.15).sub.4. In any
embodiment, the trialkyl aluminums and alkyl-aluminums resulting
from bonding of at least two aluminum compounds may be used.
[0098] In any embodiment, the co-catalyst may be an organoaluminum
compound that is halogen free. Suitable halogen free organoaluminum
compounds are, in particular, branched unsubstituted alkylaluminum
compounds of the formula AlR.sub.3, where R denotes an alkyl
radical having 1 to 10 carbon atoms, such as for example,
trimethylaluminum, triethylaluminum, triisobutylaluminum and
tridiisobutylaluminum. Additional compounds that are suitable for
use as a co-catalyst are readily available and amply disclosed in
the prior art including U.S. Pat. No. 4,990,477, which is
incorporated herein by reference for purposes of U.S. patent
practice. In any embodiment, the organoaluminum Ziegler-Natta
co-catalyst may be trimethyl aluminum, triethylaluminum (TEAL), or
a combination thereof.
Internal Electron Donors
[0099] Internal electron donors suitable for use herein generally
may be used in two ways in the formation of Ziegler-Natta catalysts
and catalyst systems. In any embodiment, an internal electron donor
may be used in the formation reaction of the catalyst as the
transition metal halide is reacted with the metal hydride or metal
alkyl. Examples of suitable internal electron donors include
amines, amides, ethers, esters, ketones, nitriles, phosphines,
stilbenes, arsines, phosphoramides, thioethers, thioesters,
aldehydes, alcoholates, and salts of organic acids. In any
embodiment, the internal donor may be a phthalate. In any
embodiment, the internal donor may be non-aromatic. In any
embodiment, the non-aromatic internal electron donor may comprise
an aliphatic amine, amide, ester, ether, ketone, nitrile,
phosphine, phosphoramide, thioethers, thioester, aldehyde,
alcoholate, carboxylic acid, or a combination thereof.
[0100] In any embodiment, the solid titanium catalyst component may
be prepared using a non-aromatic internal electron donor. Examples
of suitable non-aromatic internal electron donors include
oxygen-containing electron donors such as alcohols, ketones,
aldehydes, carboxylic acids, esters of organic or inorganic oxides,
ethers, acid amides and acid anhydrides; nitrogen-containing
electron donors such as ammonia, amines, nitriles, and/or
isocyanates. Suitable examples include alcohols having 1 to 18
carbon atoms such as methanol, ethanol, propanol, pentanol,
hexanol, octanol, 2-ethylhexanol, dodecanol, octadecyl alcohol, and
the like; ketones having 3 to 15 carbon atoms such as acetone,
methyl ethyl ketone, methyl isobutyl ketone, and the like;
aldehydes having 2 to 15 carbon atoms such as acetaldehyde,
propionaldehyde, octylaldehyde, and the like; organic acid esters
having 2 to 30 carbon atoms including the esters desired to be
included in the titanium catalyst component, such as methyl
formate, ethyl formate, vinyl acetate, propyl acetate, octyl
acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate,
ethyl valerate, ethyl stearate, methyl chloroacetate, ethyl
dichloroacetate, methyl methacrylate, ethyl crotonate, dibutyl
maleate, diethyl butylmalonate, diethyl dibutylmalonate,
ethylcyclo-hexanecarboxylate, diethyl 1,2-cyclohexanedicarboxylate,
di(2-ethylhexyl) 1,2-cyclohexanedicarboxylate, gamma-butyrolactone,
delta-valerolactone, and/or ethylene carbonate; inorganic acid
esters such as ethyl silicate and butyl silicate; acid halides
having 2 to 15 carbon atoms such as acetyl chloride and the like;
ethers having 2 to 20 carbon atoms, such as methyl ether, ethyl
ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran
and the like; acid amides such as acetamide, and the like; acid
anhydrides such as acetic anhydride, and the like; amines such as
methylamine, ethyl-amine, triethylamine, tributylamine,
tetramethyl-ethylenediamine, and the like; and nitriles such as
acetonitrile, trinitrile, and the like.
[0101] In any embodiment, the non-aromatic internal electron donor
may comprise a C.sub.1-C.sub.20 diester of a substituted or
unsubstituted C.sub.2-C.sub.10 dicarboxylic acid. In any
embodiment, the non-aromatic internal electron donor may be a
succinate according to formula (I):
##STR00002##
[0102] wherein R.sup.1 and R.sup.2 are independently
C.sub.1-C.sub.20 linear or branched alkyl, alkenyl, or cycloalkyl
hydrocarbyl radicals;
[0103] R.sup.3 to R.sup.6 are independently, hydrogen, halogen, or
C.sub.1-C.sub.20 linear or branched alkyl, alkenyl, or cycloalkyl
hydrocarbyl radicals, wherein the R.sup.3 to R.sup.6 radicals are
not joined together, wherein at least two of the R.sup.3 to R.sup.6
radicals are joined to form a cyclic divalent radical, or a
combination thereof.
[0104] In any embodiment, R.sup.3 to R.sup.5of formula I may be
hydrogen and R.sup.6 may be a radical selected from the group
consistent of a primary branched, secondary or tertiary alkyl, or
cycloalkyl radical having from 3 to 20 carbon atoms.
[0105] In any embodiment, the internal donor may be a
monosubstituted non-aromatic succinate compound. Suitable examples
include diethyl secbutylsuccinate, diethylhexylsuccinate, diethyl
cyclopropylsuccinate, diethyl trimethylsilylsuccinate, diethyl
methoxysuccinate, diethyl cyclohexylsuccinate,
diethyl(cyclohexylmethyl) succinate, diethyl t-butylsuccinate,
diethyl isobutylsuccinate, diethyl isopropylsuccinate, diethyl
neopentylsuccinate, diethyl isopentylsuccinate, diethyl
(1,1,1-trifluoro-2-propyl) succinate, diisobutyl
sec-butylsuccinate, diisobutylhexylsuccinate, diisobutyl
cyclopropylsuccinate, diisobutyl trimethylsilylsuccinate,
diisobutyl methoxysuccinate, diisobutyl cyclohexylsuccinate,
diisobutyl(cyclohexylmethyl) succinate, diisobutyl
t-butylsuccinate, diisobutyl isobutylsuccinate, diisobutyl
isopropylsuccinate, diisobutyl neopentylsuccinate, diisobutyl
isopentylsuccinate, diisobutyl (1,1,1-trifluoro-2-propyl)
succinate, dineopentyl sec-butylsuccinate, dineopentyl
hexylsuccinate, dineopentyl cyclopropylsuccinate, dineopentyl
trimethylsilylsuccinate, dineopentyl methoxysuccinate, dineopentyl
cyclohexylsuccinate, dineopentyl(cyclohexylmethyl) succinate,
dineopentyl t-butylsuccinate, dineopentyl isobutylsuccinate,
dineopentyl isopropylsuccinate, dineopentyl neopentylsuccinate,
dineopentyl isopentylsuccinate, and/or dineopentyl
(1,1,1-trifluoro-2propyl) succinate.
[0106] In any embodiment, the internal electron donor having a
structure consistent with formula (I) may comprise at least two
radicals from R.sup.3 to R.sup.6, which are different from hydrogen
and are selected from C.sub.1-C.sub.20 linear or branched alkyl,
alkenyl, and/or cycloalkyl hydrocarbyl groups, which may contain
heteroatoms. In any embodiment, two radicals different from
hydrogen may be linked to the same carbon atom. Suitable examples
include 2,2-disubstituted succinates including diethyl
2,2-dimethylsuccinate, diethyl 2-ethyl-2-methylsuccinate, diethyl
2-(cyclohexylmethyl)-2-isobutylsuccinate, diethyl
2-cyclopentyl-2-n-propylsuccinate, diethyl 2,2-diisobutylsuccinate,
diethyl 2-cyclohexyl-2-ethylsuccinate, diethyl
2-isopropyl-2-methylsuccinate, diethyl 2,2-diisopropyl diethyl 2
isobutyl-2-ethylsuccinate, diethyl
2-(1,1,1-trifluoro-2-propyl)-2-methylsuccinate, diethyl 2
isopentyl-2-isobutylsuccinate, diisobutyl 2,2-dimethylsuccinate,
diisobutyl 2-ethyl-2-methylsuccinate, diisobutyl
2-(cyclohexylmethyl)-2-isobutylsuccinate, diisobutyl
2-cyclopentyl-2-n-propylsuccinate, diisobutyl
2,2-diisobutylsuccinate, diisobutyl 2-cyclohexyl-2-ethylsuccinate,
diisobutyl 2-isopropyl-2-methylsuccinate, diisobutyl
2-isobutyl-2-ethylsuccinate, diisobutyl
2-(1,1,1-trifluoro-2-propyl)-2-methylsuccinate, diisobutyl
2-isopentyl-2-isobutylsuccinate, diisobutyl
2,2-diisopropylsuccinate, dineopentyl 2,2-dimethylsuccinate,
dineopentyl 2-ethyl-2-methylsuccinate, dineopentyl
2-(cyclohexylmethyl)-2-isobutylsuccinate, dineopentyl
2-cyclopentyl-2-n-propylsuccinate, dineopentyl
2,2-diisobutylsuccinate, dineopentyl 2-cyclohexyl-2-ethylsuccinate,
dineopentyl 2-isopropyl-2-methylsuccinate, dineopentyl
2-isobutyl-2-ethylsuccinate, dineopentyl
2-(1,1,1-trifluoro-2-propyl)-2-methylsuccinate, dineopentyl
2,2-diisopropylsuccinate, and/or dineopentyl 2-isopentyl-2
isobutylsuccinate.
[0107] In any embodiment, at least two radicals different from
hydrogen may be linked to different carbon atoms between R.sup.3
and R.sup.6. Examples include R.sup.3 and R.sup.5or R.sup.4 and
R.sup.6. Suitable non-aromatic succinate compounds include: diethyl
2,3-bis-(trimethylsilyl) succinate, diethyl
2,2-secbutyl-3-methylsuccinate, diethyl
2-(3,3,3-trifluoropropyl)-3-methylsuccinate, diethyl
2,3-bis(2-ethylbutyl)succinate, diethyl
2,3-diethyl-2-isopropylsuccinate, diethyl
2,3-diisopropyl-2-methylsuccinate, diethyl
2,3-dicyclohexyl-2-methylsuccinate, diethyl
2,3-diisopropylsuccinate, diethyl 2,3-bis-(cyclohexylmethyl)
succinate, diethyl 2,3-di-tbutylsuccinate, diethyl
2,3-diisobutylsuccinate, diethyl 2,3-dineopentylsuccinate, diethyl
2,3-diisopentylsuccinate, diethyl
2,3-(1-trifluoromethyl-ethyl)succinate, diethyl
2-isopropyl-3-isobutylsuccinate, diethyl 2-t-butyl-3
isopropylsuccinate, diethyl 2-isopropyl-3-cyclohexylsuccinate,
diethyl 2-isopentyl-3-cyclohexylsuccinate, diethyl
2-cyclohexyl-3-cyclopentylsuccinate, diethyl
2,2,3,3-tetramethylsuccinate, diethyl 2,2,3,3-tetraethylsuccinate,
diethyl 2,2,3,3-tetrapropylsuccinate, diethyl
2,3-diethyl-2,3-diisopropylsuccinate, diisobutyl
2,3-bis(trimethylsilyl)succinate, diisobutyl
2,2-sec-butyl-3-methylsuccinate, diisobutyl
2-(3,3,3-trifluoropropyl)-3-methylsuccinate, diisobutyl
2,3-bis(2-ethylbutyl)succinate, diisobutyl
2,3-diethyl-2-isopropylsuccinate, diisobutyl
2,3-diisopropyl-2-methylsuccinate, diisobutyl
2,3-dicyclohexyl-2-methylsuccinate, diisobutyl
2,3-diisopropylsuccinate, diisobutyl
2,3-bis-(cyclohexylmethyl)succinate, diisobutyl
2,3-di-t-butylsuccinate, diisobutyl 2,3-diisobutylsuccinate,
diisobutyl 2,3-dineopentylsuccinate, diisobutyl
2,3diisopentylsuccinate, diisobutyl 2,3-(1,1,1-trifluoro-2-propyl)
succinate, diisobutyl 2,3-n-propylsuccinate, diisobutyl
2-isopropyl-3-ibutylsuccinate, diisobutyl
2-terbutyl-3-ipropylsuccinate, diisobutyl
2-isopropyl-3-cyclohexylsuccinate, diisobutyl
2-isopentyl-3-cyclohexylsuccinate, diisobutyl 2-n-propyl-3
(cyclohexylmethyl)succinate, diisobutyl
2-cyclohexyl-3-cyclopentylsuccinate, diisobutyl
2,2,3,3-tetramethylsuccinate, diisobutyl
2,2,3,3-tetraethylsuccinate, diisobutyl
2,2,3,3-tetrapropylsuccinate, diisobutyl
2,3-diethyl-2,3-diisopropylsuccinate, dineopentyl
2,3-bis(trimethylsilyl)succinate, dineopentyl
2,2-di-sec-butyl-3-methylsuccinate, dineopentyl
2-(3,3,3-trifluoropropyl)-3-methylsuccinate, dineopentyl
2,3-bis-(2-ethylbutyl)succinate, dineopentyl
2,3-diethyl-2-isopropylsuccinate, dineopentyl
2,3-diisopropyl-2-methylsuccinate, dineopentyl
2,3-dicyclohexyl-2-methylsuccinate, dineopentyl
2,3-diisopropylsuccinate, dineopentyl
2,3-bis(cyclohexylmethyl)succinate, dineopentyl
2,3-di-t-butylsuccinate, dineopentyl 2,3-diisobutylsuccinate,
dineopentyl 2,3-dineopentylsuccinate, dineopentyl
2,3-diisopentylsuccinate, dineopentyl
2,3-(1,1,1-trifluoro-2propyl)succinate, dineopentyl
2,3-n-propylsuccinate, dineopentyl 2-isopropyl-3-isobutylsuccinate,
dineopentyl 2-t-butyl-3-isopropylsuccinate, dineopentyl
2-isopropyl-3-cyclohexylsuccinate, dineopentyl 2-isopentyl-3
cyclohexylsuccinate, dineopentyl
2-n-propyl-3-(cyclohexylmethyl)succinate, dineopentyl 2
cyclohexyl-3-cyclopentylsuccinate, dineopentyl
2,2,3,3-tetramethylsuccinate, dineopentyl
2,2,3,3-tetraethylsuccinate, dineopentyl
2,2,3,3-tetrapropylsuccinate, and/or dineopentyl 2,3-diethyl
2,3-diisopropylsuccinate.
[0108] In any embodiment, the compounds according to formula (I)
may include two or four of the radicals R.sup.3 to R.sup.6 joined
to the same carbon atom which are linked together to form a cyclic
multivalent radical. Examples of suitable compounds include
1-(ethoxycarbonyl)-1-(ethoxyacetyl)-2,6-dimethylcyclohexane,
1-(ethoxycarbonyl)-1-(ethoxyacetyl)-2,5-dimethyl-cyclopentane,
1-(ethoxycarbonyl)-1-(ethoxyacetylmethyl)-2-methylcyclohexane,
and/or
1-(ethoxycarbonyl)-1-(ethoxy(cyclohexyl)acetyl)cyclohexane.
[0109] For purposes herein, all the above mentioned compounds can
be used either in the form of pure stereoisomers or in the form of
mixtures of enantiomers, or a mixture of diastereoisomers and
enantiomers. When a pure isomer is to be used, it may be isolated
using the common techniques known in the art. In particular, some
of the succinates of the present invention can be used as a pure
rac or meso forms, or as mixtures thereof, respectively.
[0110] In any embodiment, the internal electron donor compound may
be selected from the group consisting of diethyl
2,3-diisopropylsuccinate, diisobutyl 2,3-diisopropylsuccinate,
di-n-butyl 2,3-diisopropylsuccinate, diethyl
2,3-dicyclohexyl-2-methylsuccinate, diisobutyl
2,3-dicyclohexyl-2-methylsuccinate, diisobutyl
2,2-dimethylsuccinate, diethyl 2,2-dimethylsuccinate, diethyl
2-ethyl-2-methylsuccinate, diisobutyl 2-ethyl-2-methylsuccinate,
diethyl 2-(cyclohexylmethyl)-3-ethyl-3-methylsuccinate, diisobutyl
2-(cyclohexylmethyl)-3-ethyl-3-methylsuccinate, and combinations
thereof.
External Electron Donors
[0111] In any embodiment, in conjunction with an internal donor,
two or more external electron donors may also be used in
combination with a catalyst. External electron donors include, but
are not limited to, organic silicon compounds, e.g.,
tetraethoxysilane (TEOS), methylcyclohexyldimethoxysilane (MCMS),
propyltriethoxysilane (PTES) and dicyclopentydimethoxysilane
(DCPMS). Internal and external-type electron donors are described,
for example, in U.S. Pat. No. 4,535,068, which is incorporated
herein by reference for purposes of U.S. patent practice. The use
of organic silicon compounds as external electron donors is
described, for example, in U.S. Pat. Nos. 4,218,339, 4,395,360,
4,328,122 and 4,473,660, all of which are incorporated herein by
reference for purposes of U.S. patent practice. The external
electron donors act to control stereoregularity, which affects the
amount of isotactic versus atactic polymers produced in a given
system. The more stereoregular isotactic polymer is more
crystalline, which leads to a material with a higher flexural
modulus. Highly crystalline, isotactic polymers also display lower
MFRs, as a consequence of a reduced hydrogen response during
polymerization. The stereoregulating capability and hydrogen
response of a given external electron donor are directly and
inversely related. The DCPMS donor has a substantially lower
hydrogen response than the PTES donor, but produces a significantly
higher level of stereoregularity than PTES.
[0112] In any embodiment, the two external electron donors A and B,
also referred to herein as the first external electron donor and
the second external electron donor, may be selected such that the
melt flow rate MFR (A) of homopolypropylene obtained by
homopolymerizing propylene by using the first external electron
donor (A) in combination with the solid titanium catalyst component
and the organoaluminum compound catalyst component and the MFR (B)
of homopolypropylene obtained by homopolymerizing propylene by
using the second external electron donor (B) under the same
conditions as in the case of using the external electron donor (A)
have the following relation:
1.2.ltoreq.log [MFR(B)/MFR(A)].ltoreq.1.4.
[0113] The external electron donors to be used in the preparation
of the electron donor catalyst component may be those electron
donors which are used in preparing the solid titanium catalyst
component. In any embodiment, each of the external electron donors
(A) and (B) may comprise organic silicon compounds.
[0114] In any embodiment, one or more of the external electron
donors may comprise an organic silicon compound of formula:
R.sup.3.sub.nSi(OR.sup.4).sub.4-n
wherein R.sup.3 and R.sup.4 independently represent a hydrocarbyl
radical and 0<n<4.
[0115] Examples of the suitable organic silicon compounds include
trimethylmethoxysilane, trimethylethoxysilane,
dimethyldimethoxysilane, dimethyldimethoxysilane,
dimethyldiethoxysilane, diiso-propyldiethoxysilane,
t-butylmethyl-n-diethoxysilane, t-butylmethyldiethoxysilane,
t-amylmethyldiethoxysilane, diphenyldimethoxysilane,
phenylmethyldimethoxysilane, diphenyldiethoxysilane,
bis-o-tolyldimethoxysilane, bis-m-tolyldimethoxysilane,
bis-p-tolyldimethoxysilane, bis-p-tolyldimethoxysilane,
bisethylphenyldimethoxy-silane, dicyclohexyldiethoxysilane,
cyclohexylmethyl-dimethoxysilane, cyclohexylmethyldiethoxysilane,
ethyltrimethoxysilane, ethyltriethoxysilane,
vinyl-trimethoxysilane, methyltrimethoxysilane,
n-propyl-triethoxysilane, decyltrimethoxysilane,
decyltriethoxy-silane, phenyltrimethoxysilane,
[gamma]-chloropropyltri-methoxysilane, methyltriethoxysilane,
ethyltriethoxy-silane, vinyltriethoxysilane,
t-butyltriethoxysilane, n-butyltriethoxysilane,
iso-butyltriethoxysilane, phenyltriethoxysilane,
gamma-aminopropyltriethoxysilane, chlorotriethoxysilane,
vinyltributoxysilane, cyclo-hexyltrimethoxysilane,
cyclohexyltriethoxysilane, 2-norbornanetriethoxysilane,
2-norbornanemethyldimethoxy-silane, ethyl silicate, butyl silicate,
trimethyl-phenoxysilane, methylallyloxysilane,
vinyltris(beta-methoxyethoxysilane), vinyltriacetoxysilane, and/or
dimethyltetraethoxydisiloxane.
[0116] In any embodiment, one of the two or more organic silicon
compounds may comprise the formula:
R.sup.1.sub.2Si(OR.sup.2).sub.2
wherein R.sup.1 represents a hydrocarbyl radical in which the
carbon adjacent to Si is secondary or tertiary. Suitable examples
include substituted and unsubstituted alkyl groups such as
isopropyl, sec-butyl, t-butyl and t-amyl groups, cyclo-alkyl groups
such as cyclopentyl and cyclohexyl groups, cycloalkenyl groups such
as a cyclopentenyl group, and aryl groups such as phenyl and tolyl
groups. In any embodiment, R.sup.2 may represent a hydrocarbyl
radical, or a hydrocarbyl radical having 1 to 5 carbon atoms, or a
hydrocarbyl radical having 1 or 2 carbon atoms.
[0117] Examples of suitable organic silicon compound include
diisopropyldimethoxysilane, diisopropyldiethoxysilane,
di-sec-butyldimethoxysilane, di-t-butyldimethoxysilane,
di-t-amyldimethoxysilane, dicyclopentyldimethoxysilane,
dicyclohexyldimethoxy-silane, diphenyldimethoxysilane,
bis-o-tolyldimethoxy-silane, bis-m-tolyldimethoxysilane,
bis-p-tolyldi-methoxysilane, and/or
bis-ethylphenyldimethoxysilane.
[0118] In any embodiment, the organic silicon compound may be
represented by the following general formula:
R.sup.1.sub.nSi(OR.sup.2).sub.4-n
wherein n is 2, R.sup.1 each represents a hydrocarbyl radical, and
at least one of the two hydrocarbyl radicals is a hydrocarbon group
in which the carbon adjacent to Si is a primary carbon. Examples of
suitable hydrocarbon groups include alkyl groups such as ethyl,
n-propyl and n-butyl groups, aralkyl groups such as cumyl and
benzyl groups, and alkenyl groups such as a vinyl group, and the
like.
[0119] In any embodiment, R.sup.2 may represent a hydrocarbyl
radical preferably having 1 to 5 carbon atoms, or from 1 to 2
carbon atoms. Suitable examples of the organic silicon compounds in
which n is 2 include diethyldimethoxysilane,
dipropyldimethoxysilane, di-n-butyldimethoxysilane,
dibenzyldimethoxysilane and/or divinyldimethoxysilane.
[0120] Examples of suitable compounds when 0.ltoreq.n<2 or
2<n<4 include R.sup.1 being an alkyl, cycloalkyl, alkenyl,
aryl or aralkyl group and R.sup.2 represents a hydrocarbyl radical
having 1 to 5 carbon atoms, or 1 to 2 carbon atoms.
[0121] Suitable examples of the organic silicon compounds in which
0.ltoreq.n<2 or 2<n<4 include trimethylmethoxysilane,
trimethylethoxysilane, methyl-phenyldimethoxysilane,
methyltrimethoxysilane, t-butyl-methyldimethoxysilane,
t-butylmethyldiethoxysilane, t-amylmethyldimethoxysilane,
phenylmethyldimethoxysilane, cyclohexylmethyldimethoxysilane,
cyclohexylmethyldi-ethoxysilane, ethyltrimethoxysilane,
ethyltriethoxy-silane, vinyltriethoxysilane,
methyltrimethoxysilane, methyltriethoxysilane,
propyltrimethoxysilane, decyl-trimethoxysilane,
decyltriethoxysilane, phenyltri-methoxysilane,
propyltriethoxysilane, butyltriethoxy-silane,
phenyltriethoxysilane, vinyltrimethoxysilane, vinyltributoxysilane,
cyclohexyltrimethoxysilane, 2-norbornanetrimethoxysilane, and/or
2-norbornanetriethoxy-silane.
[0122] In any embodiment, the external electron donors include
methyltrimethoxysilane, ethyltrimethoxysilane,
ethyltriethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane,
decyl-trimethoxysilane, decyltriethoxysilane,
propyltri-ethoxysilane, butyltriethoxysilane,
phenyltriethoxy-silane, vinyltrimethoxysilane, vinyltributoxysilane
and/or cyclohexyltrimethoxysilane.
[0123] In any embodiment, the above disclosed organic silicon
compounds may be used such that a compound capable of being changed
into such an organic silicon compound is added at the time of
polymerizing or preliminarily polymerizing an olefin, and the
organic silicon compound may be formed in-situ during the
polymerization or the preliminary polymerization of the olefin.
[0124] In any embodiment, a first external electron donor may have
the formula R.sup.1.sub.2Si(OR.sup.2).sub.2, wherein each R.sup.1
is independently a hydrocarbyl radical comprising from 1 to 10
carbon atoms in which the carbon adjacent to the Si is a secondary
or a tertiary carbon atom, and wherein each R.sup.2 is
independently a hydrocarbyl radical comprising from 1 to 10 carbon
atoms; and
[0125] a second external electron donor having the formula
R.sup.3.sub.nSi(OR.sup.4).sub.4-n,
[0126] wherein each R.sup.3 and R.sup.4 are independently a
hydrocarbyl radical comprising from 1 to 10 carbon atoms, and
[0127] n is 1, 2, or 3; and the second external electron donor is
different than the first external electron donor.
[0128] In any embodiment, the first external electron donor and the
second external electron donor may be selected from the group
consisting of tetraethoxysilane, methylcyclohexyldimethoxysilane,
propyltriethoxysilane, dicyclopentydimethoxysilane, and
combinations thereof. In any embodiment, the Ziegler-Natta catalyst
system may comprise about 2.5 mol % to less than 50 mo % of the
first external electron donor and greater than 50 mol % of a second
external electron donor based on total mol % of external electron
donors. In any embodiment, the first electron donor may comprise,
consist of, or consist essentially of dicyclopentyldimethoxysilane
(DCPMS) and the second external electron donor may comprise,
consist of, or consist essentially of propyltriethoxysilane
(PTES).
[0129] In any embodiment, a relationship between the first external
electron donor and the second external electron donor may be
defined by the equation:
1.2.ltoreq.log [MFR(B)/MFR(A)].ltoreq.1.4
[0130] wherein MFR(A) is a first melt flow rate of a homopolymer
formed by polymerizing propylene monomers in the presence of the
Ziegler-Natta catalyst and the first external electron donor, and
wherein MFR(B) is a second melt flow rate of a homopolymer formed
by polymerizing propylene monomers in the presence of the
Ziegler-Natta catalyst and the second external electron donor, and
wherein the MFR(A) is lower than the MFR(B).
Example
[0131] A high activity catalyst system known to produce highly
crystalline isotactic polypropylene with very high yield, 30 to 45
kg polymer per g of catalyst solids, was selected for trial in a
commercial scale polypropylene facility that included a CSTR
pre-contacting pot ("PCP"), a pre-polymerization loop reactor
downstream of the PCP, and a primary polymerization slurry loop
reactor downstream of the pre-polymerization reactor. In a first
attempt, a Generation V Ziegler-Natta catalyst having a succinate
internal donor, triethylaluminum activator, and external electron
donors were pre-contacted continuously in the PCP for a residence
time of 10 to 20 minutes. The resulting activated catalyst was then
injected into a high velocity refrigerated monomer stream
containing propylene, propane, hydrogen, at approximately 7.degree.
C. Within several minutes of initiating the flow of catalyst
solids, the catalyst injector plugged at the point where the
activated catalyst came into contact with the refrigerated monomer.
This process was repeated multiple times with the same result.
[0132] The process was then reconfigured such that the activator
and external electron donor were allowed to continue flowing
through the prior flow path (i.e., first to the PCP and then into
the refrigerated monomer stream of the pre-polymerization reactor
via the catalyst injector) and the catalyst solids were diverted to
a secondary refrigerated monomer stream via a secondary catalyst
injector, completely bypassing the activator pre-contacting step.
Despite the lack of pre-contacting, the catalyst became adequately
activated in the pre-polymerization reactor with sufficient
pre-polymerization yield (>250 g polymer/g catalyst solids) to
ensure acceptable product granule morphology (unbroken polymer
particles and low quantity of fines), and external electron donor
complexation was sufficient to provide the desired product
crystallinity with no difference in product properties of
significance.
[0133] The polymer produced in the above-described reconfigured
process compared favorably to samples made with the same catalyst
system in a pilot plant employing the catalyst and activator
pre-contacting step. In the following Table 1, polymer samples
produced in four example runs, in which the catalyst bypassed the
PCP, is compared to two polymer samples produced in two pilot plant
scale runs in which the catalyst was allowed to pre-contact the
activator for a typical residence time of 10 to 20 minutes in the
PCP before injection into the reactor. In the comparative examples,
inerts were added to the catalyst feed to enable injection of the
pre-activated catalysts without unmanageable plugging.
TABLE-US-00001 TABLE 1 Comparative 1 Comparative 2 Example 1
Example 2 Example 3 Example 4 Process scale Pilot Plant Pilot Plant
Pilot Plant Commercial Commercial Commercial Scale Plant Scale
Plant Scale Plant Pre-contacting pot No No YES YES YES YES Bypass
Melt Flow Rate 2.0 2.2 1.6 1.9 2.0 2.65 (g/10 min).sup.1 Poly
Dispersity 8.3 8.4 8.4 8 8.6 8.6 Indiex (PDI).sup.2 Zero Shear
31000 28800 40200 33800 30200 25300 Viscosity at 190.degree. C.
(Pa-s) Tan Delta at 3.6 3.8 3.5 3.64 3.7 3.9 190.degree. C. at 0.01
rad/s Relaxation time at 4.4 4.4 6.3 4.4 3.8 4.5 190.degree. C.
(seconds)
[0134] In the foregoing table, Melt Flow Rate was measured as per
ASTM D1238. Poly dispersity index was measured from oscillatory
shear rheology at 190.degree. C., using the cross-over frequency
and modulus for the G' and G'', as per Zeicher and Patel (G. R.
Zeichner and P. D. Patel, Proceedings of the 2.sup.nd World
Congress on Chemical Engineering 6:333). Zero shear viscosity, Tan
delta, and relaxation time are measured by oscillatory shear
rheology as measured at 190.degree. C. The PDI, zero shear
viscosity, tan delta and relaxation time are similar for the
polypropylene made with and without pre-contacting in the pilot
plant and without pre-contacting in the commercial scale plant.
[0135] It has therefore been demonstrated that suitable activation
of highly active catalyst systems can be achieved without any
pre-contacting time. It is envisioned that other injection schemes
can also be employed, including those disclosed herein, that
similarly allow for activation of the catalyst in situ the reactor
without any pre-contacting time. Further, it is envisioned that
injection schemes that allow only minimal pre-contacting time,
e.g., schemes that allow some pre-activation of a portion of the
catalyst feed prior to injection into the reactor, may achieve some
or all of the advantages of avoiding pre-contacting. For example,
pre-contacting time may be limited to less than 1 minute, or even
more preferably less than 10 seconds or less than 5 seconds of
pre-contacting time.
[0136] FIG. 1 shows a temperature vs. catalyst activity plot for
two highly active catalyst systems, one of which was utilized in
producing the polymers of Examples 1 to 4 (highly active catalyst
system B). The highly active catalyst system A, which is a
Generation IV Ziegler-Natta catalyst system having a phthalate
internal donor, can be injected to the pre-polymerization reactor
of the previously described commercial scale plant after 10 to 20
minutes pre-contacting time; however, reaction conditions must
generally be significantly tempered to avoid plugging. As
illustrated in FIG. 2, when regressing the catalyst activity data
to estimate the activity of the catalyst at the injection site, the
standard adjusted catalyst activity of the highly active catalyst
system A (i.e., the catalyst activity at approximately 5.degree. C.
monomer feed stream temperature and 10 to 20 minutes of
pre-contacting time of the catalyst and activator) is approximately
20 gPgcat.sup.-1hr.sup.-1, with a margin of error extending from
about 10 gPgcat.sup.-1hr.sup.-1 to about 40 gPgcat.sup.-1hr.sup.-1.
This catalyst system had a catalyst activity of greater than 20,000
gPgcat.sup.-1hr.sup.-1 at 70.degree. C.
[0137] As illustrated in FIG. 3, when regressing the catalyst
activity data to estimate the activity of the catalyst at the
injection site, the standard adjusted catalyst activity of the
highly active catalyst system B (i.e., the catalyst activity at
approximately 5.degree. C. monomer feed stream temperature and 10
to 20 minutes of pre-contacting time of the catalyst and activator)
is approximately 160 gPgcat.sup.-1hr.sup.-1, with a margin of error
extending as low as 70 gPgcat.sup.-1hr.sup.-1. This catalyst system
had a catalyst activity of greater than 20,000
gPgcat.sup.-1hr.sup.-1 at 70.degree. C. Because injector plugging
occurred with this catalyst system at these injection conditions,
it is predicted that other catalyst systems having similar or
greater standard adjusted catalyst activity will likewise exhibit
plugging under the same injection conditions and environment.
Furthermore, because the highly active catalyst system achieves
suitable activation without any pre-contacting time, it is
predicted that catalysts having higher standard adjusted catalyst
activity should similarly achieve suitable activation without
pre-contacting. Similarly, it is predicted that catalyst systems
having standard adjusted catalyst activity of greater than 10
gPgcat.sup.-1hr.sup.-1 can achieve sufficient activation without
complete pre-activation, particularly using limited pre-contacting
time, e.g., less than 10 seconds of pre-contacting time.
[0138] All documents described herein are incorporated by reference
herein, including any priority documents, related applications
and/or testing procedures to the extent they are not inconsistent
with this text. As is apparent from the foregoing general
description and the specific embodiments, while forms of the
invention have been illustrated and described, various
modifications can be made without departing from the spirit and
scope of the invention. Accordingly, it is not intended that the
invention be limited thereby. Likewise, "comprising" encompasses
the terms "consisting essentially of," "is," and "consisting of"
and anyplace "comprising" is used "consisting essentially of,"
"is," or "consisting of" may be substituted therefor.
* * * * *